This invention relates to radiological imaging systems, and more particularly a method and apparatus for utilizing of such systems to track and control the location of needle probes within the body. These radiological imaging systems are used so that probes which are inserted into or through body tissue and maneuvered therein are illustrated on a scintigraphic viewing system to disclose the position of the probe in the organ or other tissue within which the probe is to be positioned. An example of the procedures which are used with the method and apparatus of the present invention is in aspiration biopsy
In aspiration biopsy, a small hollow needle is inserted directly into the body to the desired tissue or organ, whereupon a tissue sample is withdrawn, such as by vacuum aspiration. The needle is then withdrawn, but because of its relatively insignificant diameter, wound closure occurs normally by muscular and tissue tension, generally without the need for sutures, cauterization or the like. For optimal effectiveness, aspiration biopsy requires that the tip of the needle by precisely accurately placed in the organ to be sampled. When properly performed, these techniques are safe, effective and minimally traumatic.
Various radiological techniques such as X-ray fluoroscopic techniques have been used for ascertaining or estimating the location of tissue to be treated, sampled or diagnosed, and or aiding in the maneuvering of a given probe to its desired body location. These radiological techniques do not permit the organ as well as the needle to be actually visible and suffer from dimensional and accuracy limitations.
A variety of ultrasound images techniques have been suggested, particularly for in vivo imaging of relatively deep soft body tissue. Various ultrasound systems are disclosed in U.S. Pat. No. 4,407,294 issued Oct. 4, 1983 to Vilkomerson, in U.S. Pat. No. 4,431,006 issued Feb. 14, 1984 to Trimmer et al, and U.S. Pat. No. 4,431,005 issued Feb. 14, 1984 to McCormick. These prior art systems have experienced a certain degree of commercial success and are normally effective for their intended uses, but all suffer from various limitations inherent in the ultrasound process and require special electronics and compact, expensive transducer elements.